title: Airborne emissions from 1961 to 2004 of benzo[a]pyrene from U.S. vehicles per km of travel based on tunnel studies.
abstract: We identified 13 historical measurements of polycyclic aromatic hydrocarbons (PAHs) in U.S. vehicular traffic tunnels that were either directly presented as tailpipe emission factors in microg per vehicle-kilometer or convertible to such a form. Tunnel measurements capture fleet cruise emissions. Emission factors for benzo[a]pyrene (BaP) for a tunnel fleet operating under cruise conditions were highest prior to the 1980s and fell from more than 30-microg per vehicle-km to approximately 2-microg/km in the 1990s, an approximately 15-fold decline. Total annual U.S. (cruise) emissions of BaP dropped by a lesser factor, because total annual km driven increased by a factor of 2.7 during the period. Other PAH compounds measured in tunnels over the 40-year period (e.g., benzo[ghi]perylene, coronene) showed comparable reduction factors in emissions. PAH declines were comparable to those measured in tunnels for carbon monoxide, volatile organic compounds, and particulate organic carbon. The historical PAH "source terms" determined from the data are relevant to quantifying the benefits of emissions control technology and can be used in epidemiological studies evaluating the health effects of exposure, such as those undertaken with breast cancer in New York State.
authors.affiliation: Consulting in the Public Interest (CIPI), Lambertville, New Jersey, Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY 10032, USA. jbeyea@cipi.com
authors.forename: Jan
authors.initials: J
authors.lastname: Beyea
authors.forename: Steven D
authors.initials: SD
authors.lastname: Stellman
authors.forename: Maureen
authors.initials: M
authors.lastname: Hatch
authors.forename: Marilie D
authors.initials: MD
authors.lastname: Gammon
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D001564:Benzo(a)pyrene / Q000032:analysis*; D004784:Environmental Monitoring; D018986:Motor Vehicles; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis; D014195:Travel; D014481:United States; D001335:Vehicle Emissions / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D011084:Polycyclic Aromatic Hydrocarbons; D001335:Vehicle Emissions; D001564:Benzo(a)pyrene